High speed pull test device and method

Abstract

A device and method for tensile testing of the bond strength of an electrically conductive ball adhered to a substrate. A ball is gripped and moved at a speed in a direction substantially orthogonal to the plane of adherence. The substrate is abruptly halted by an abutment to impose a sudden load on the ball/substrate interface. During the test the substrate is lightly urged toward the ball to eliminate unwanted tensile forces.

1. A method of testing the bond strength of an electrical connection adhered to a substrate, the substrate having a top surface, the method comprising the steps of:
 attaching a test tool to the electrical connection, 
 moving the electrical connection in a direction substantially orthogonal to the top surface of the substrate while urging the substrate against the electrical connection, 
 abruptly halting the substrate, and 
 measuring the force required to break the electrical connection off of the substrate. 
 
     
     
       2. The method of testing according to  claim 1  and including the preparatory step of clamping the substrate to a platen, whereby the platen is abruptly halted, thereby indirectly halting the substrate. 
     
     
       3. The method of testing according to  claim 2  and including the step of providing a pneumatic ram to urge the substrate against the electrical connection, and applying air under pressure to the ram in an amount sufficient to ensure a compressive load between the electrical connection and substrate up to the time when the substrate is abruptly halted. 
     
     
       4. The method of testing according to  claim 1  and including the step of providing a pneumatic ram to urge the substrate against the electrical connection, and applying air under pressure to the ram in an amount sufficient to ensure a compressive load between the electrical connection and substrate up to the time when the substrate is abruptly halted. 
     
     
       5. A method of testing the strength of the bond between an electrical connection and an electronic substrate at an electrical connection-substrate interface, the method comprising the steps of:
 securing the substrate to a platen; 
 positioning the substrate a sufficient distance from a stationary abutment to permit the substrate to be moved towards the abutment; 
 moving a test tool into engagement with the electrical connection so that the test tool can be attached to the electrical connection; 
 moving the substrate and test tool in unison towards the abutment while urging the electrical connection against the test tool and while preventing rotation of the substrate relative to the test tool; 
 causing the substrate to contact the abutment to abruptly halt the substrate; 
 continuing to move the test tool while still being attached to the electrical connection to break the electrical connection off the substrate; and 
 measuring the force required to break the electrical connection off the substrate. 
 
     
     
       6. The method of  claim 5 , wherein abruptly halting the substrate comprises contacting the substrate against an abutment. 
     
     
       7. Apparatus for testing the strength of the bond between an electrical connection and a substrate at an electrical connection-substrate interface, the substrate having a top surface, the apparatus comprising:
 a test tool adapted to be attached to an electrical connection adhered to a substrate; 
 an apparatus for moving said test tool on an axis substantially orthogonal to the top surface of the substrate; 
 an urging apparatus for urging the substrate on said axis towards said test tool, said urging apparatus adapted to move the substrate and electrical connection along said axis; 
 an abutment adapted to restrain the substrate while the apparatus for moving said test tool continues to move said test tool along said axis to break the electrical connection off the substrate; and 
 a force measuring apparatus configured to measure the force required to break the electrical connection off the substrate. 
 
     
     
       8. The apparatus according to  claim 7  wherein said urging apparatus comprises a pneumatic ram. 
     
     
       9. The apparatus according to  claim 8  wherein said abutment restrains the substrate by direct contact with said ram. 
     
     
       10. The apparatus according to  claim 7  wherein said urging apparatus includes a platen for the substrate. 
     
     
       11. The apparatus according to  claim 10  wherein said abutment restrains the substrate by direct contact with said platen. 
     
     
       12. The apparatus according to  claim 10  and further including a clamp device to releasably restrain the substrate on said platen. 
     
     
       13. The apparatus according to  claim 12  wherein said abutment restrains the substrate by direct contact with said platen. 
     
     
       14. The apparatus according to  claim 7  wherein said abutment restrains the substrate by direct contact with the substrate.